U.S. patent application number 12/664338 was filed with the patent office on 2010-09-02 for rf switch device.
Invention is credited to Niklas Philipsson.
Application Number | 20100222014 12/664338 |
Document ID | / |
Family ID | 40156434 |
Filed Date | 2010-09-02 |
United States Patent
Application |
20100222014 |
Kind Code |
A1 |
Philipsson; Niklas |
September 2, 2010 |
RF Switch Device
Abstract
In a device (11) for switching RF-signals in a radio unit (DRU)
there is provided an RF matched card holder (12) for mounting on a
printed circuit board (PCB) of the radio unit, said card holder
having multiple signal coupling contact elements (15) supported
therein; an RF matched switch card (13) to be received in
alternative positions in the card holder; multiple sets of contact
pads (16 and 17, respectively) on at least one side (13 A, 13B) of
the switch card; and signal paths (SP) extended between selected
contact pads of each set.
Inventors: |
Philipsson; Niklas;
(Knivsta, SE) |
Correspondence
Address: |
COATS & BENNETT, PLLC
1400 Crescent Green, Suite 300
Cary
NC
27518
US
|
Family ID: |
40156434 |
Appl. No.: |
12/664338 |
Filed: |
September 13, 2007 |
PCT Filed: |
September 13, 2007 |
PCT NO: |
PCT/SE2007/000804 |
371 Date: |
December 11, 2009 |
Current U.S.
Class: |
455/91 |
Current CPC
Class: |
H01R 27/00 20130101;
H01R 29/00 20130101 |
Class at
Publication: |
455/91 |
International
Class: |
H04B 1/02 20060101
H04B001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 18, 2007 |
SE |
0701530-8 |
Claims
1-6. (canceled)
7. A device for switching high power RF signals in a radio unit,
said device comprising: an RF matched card holder for mounting on a
printed circuit board of the radio unit; multiple signal coupling
contact elements supported in the card holder; an RF matched switch
card configured to be received in alternative positions in the card
holder, multiple sets of contact pads on at least one side of the
switch card; and signal paths extended between selected contact
pads of each set; wherein the multiple sets of contact pads include
at least one of: contact pads for coupling to the printed circuit
board of the radio unit a signal indicative of the position of the
switch card in the holder; and contact pads for coupling to the
printed circuit board of the radio unit a signal indicative of the
status of the switch card, with regard to its complete insertion
into the card holder.
8. The device of claim 7, wherein the multiple sets of contact pads
include one set of contact pads of the switch card on each one of a
first and a second side of the switch card.
9. The device of claim 8, wherein the switch card has a different
pattern of signal paths on each side thereof, which sets the switch
card in different operating modes depending upon the position of
the switch card in the holder.
10. The device of claim 7, wherein the switch card is or includes a
switch board in a form of a printed circuit board.
11. The device of claim 10, the switch card or switch board
includes integrated chip components.
12. The device according of claim 7, wherein the signal coupling
contact elements are contact springs that are floatingly supported
on structural parts of the card holder for contacting contact pads
on the unit circuit board and contact pads of the switch card in
use.
13. A device for switching high power RF signals in a radio unit,
said device comprising: an RF matched card holder for mounting on a
printed circuit board of the radio unit; an RF matched switch card
configured to be received in alternative positions in the card
holder by virtue of having: a first set of contact pads on a first
side of the switch card and a second set of contact pads on a
second side of the switch card; said first and second sets of
contact pads having different patterns of signal paths such that
the device will be set in different operating modes in dependence
upon the positioning of the switch card within the card holder.
Description
TECHNICAL FIELD
[0001] The present invention relates to radio units for
transmitting and receiving radio signals.
BACKGROUND
[0002] Switches are commonly used in electronic appliances for
routing RF signals. For such switches, it has in the past been well
known to use relay type electromechanical switches. Such prior art
electromechanical type switches have been very successfully used in
many applications where radio signals should be coupled in
different directions. They have primarily been considered to
benefit from being reliable and well suited for high power RF
applications and for use in higher frequency ranges. They are
therefore still used in several applications within the field of
telecommunications; in spite of their relatively high production
cost as well as comparatively large space requirement. Quality
problems have also been frequent, leading to extensive time
consumption for handling and replacing these relays and to
considerably added cost.
[0003] In related communication areas it has been common to use
semiconductor type elements, such as with transistors or diodes,
for the RF switches. Such switches do not present optimal switching
characteristics and are normally not selected for high-power
applications. Specifically, their use in higher frequency
applications is questionable on account of the fact that they
present high loss across the switch when closed and signal leakage
when open. There are also isolation issues appearing in
applications of semiconductor type switches, requiring not least
efficient shielding.
[0004] Consequently, the signal switch devices conventionally used
within the RF communications field, and specifically in high power
RF applications, are not satisfactory and there is a considerable
need for developments solving the presented problems related to the
provision of reliable RF-signal switching at reduced cost and with
a low space requirement.
SUMMARY
[0005] It is a general object of the invention to enable space
efficient and cost effective switching of multiple radio frequency
signals in electronic appliances.
[0006] In particular, it is an object of the invention to provide
an improved device for coupling multiple radio signals in different
directions in radio units, said device having low space requirement
and low production cost.
[0007] This and other objects are met by the invention as defined
in the accompanying patent claims.
[0008] To achieve the above stated objects, the invention provides
an effective, compact and reliable device for switching high power
RF signals in a radio unit. Briefly, the invention provides a
switch device comprising an RF matched card holder for mounting on
a printed circuit board and having signal contact elements
supported therein and an RF matched switch card to be received in
alternative positions in the holder and having multiple sets of
contact pads on at least one side thereof and signal paths extended
between selected contact pads of each set.
[0009] In an embodiment of the invention sets of contact pads on
the switch card are provided on upper and lower sides,
respectively, of the card.
[0010] By providing a different pattern of signal paths on each
side of the card the device will be set in different operating
modes depending upon the positioning of the card in the holder.
[0011] Preferred further developments of the basic inventive idea
as well as embodiments thereof are specified in the dependent
subclaims.
[0012] Advantages offered by the present invention, in addition to
those described above, will be readily appreciated upon reading the
below detailed description of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention, together with further objects and advantages
thereof, will be best understood by reference to the following
description taken together with the accompanying drawings, in
which:
[0014] FIG. 1 is a schematical view of a prior art relay type
switch configuration having two alternative switching modes;
[0015] FIG. 2A is a schematical view of an exemplary embodiment of
a switch configuration of the invention, likewise having two
alternative switching modes, in a first switching mode;
[0016] FIG. 2B is a schematical view of the exemplary embodiment of
the switch configuration of the invention, in a second switching
mode;
[0017] FIG. 3 is a top perspective view of an exemplary embodiment
of a switch card device of the invention; and
[0018] FIG. 4 is a partial, schematical longitudinal section
through the exemplary switch card device of FIG. 3;
[0019] FIG. 5A is a very schematical illustration of a first side
layout of an exemplary switch card for use in a switch device of
the invention; and
[0020] FIG. 5B is a very schematical illustration of a second side
layout of the exemplary switch card of FIG. 5A.
ABBREVIATIONS
[0021] PCB--Printed circuit board
[0022] DRU--Radio Unit
[0023] RF--Radio Frequency
DETAILED DESCRIPTION
[0024] Throughout this specification reference is made to RF switch
applications intended for radio units for transmitting and
receiving radio signals and specifically to high power RF signal
applications. It shall be emphasized, though that such reference is
made for the purpose of describing exemplary applications and
preferred embodiments of the invention and is not intended to limit
the invention to any specific radio communication application or to
any particular power range or specifically to the details of such
applications.
[0025] In existing radio units functioning for the transmission and
reception of radio signals and for use in i.e. the field of
telecommunications, it has been common to use a number of relay
switches with control signals from software, in situations where
radio signals should be coupled in different directions. In FIG. 1
is illustrated a typical such prior switch configuration used for
switching high power RF signals in a radio unit used within the
telecommunications field. In this switch configuration three relay
switches 1-3 with electronic switch remote are connected to a PCB
of the radio unit (not specifically illustrated). The illustrated,
typical switch configuration generally concerns a transmitting and
receiving radio unit requiring a switching configuration with a two
mode switch function. In a first mode two separate RF signals S1
and S2, respectively, are transferred from the respective inputs S1
IN and S2 IN, through the respective relay switches 1, 3 and 2, to
the respective outputs S1 OUT and S2 OUT. In a second mode the RF
signals S1 and S2 are combined in a combiner or mixer 5 and the
combined signal S1+S2 is transferred to a common output S1+S2 OUT,
through the relay switch 3 that in the first mode transfers the
first signal S1 to its output S1 OUT.
[0026] With such a conventional solution, a comparatively large PCB
area is occupied by the relay switch components 1-3 and the
component cost is high. The relay concept is based on the principle
of connecting signals by pulling contact surfaces of the relay
switches into engagement with each other by means of a solenoid.
This concept can involve a serious risk of malfunction, especially
after many years of use. There is also considerable power
consumption in each of the relays 1-3. As mentioned, quality
problems have been an issue for these relays, resulting in a high
time consumption and added cost. This, in addition to the
questionable long term functionality and comparatively high power
consumption, makes such a relay based switch configuration less
attractive.
[0027] It is a general fact that in the development of DRU units
attempts have been made in the past to try and reduce space and
cost. There are many ways of reducing cost, such as by designing
components that are less expensive to produce, reducing PCB area,
designing modules, simplifying designs, removing features and/or
functions, reducing weight etc. In accordance with the solution
presented by the invention, most, if not all of these desired,
advantageous improvements are achieved. Basically, the reduction of
the space requirement achieved by means of the solution according
to the present invention, could in future DRU projects even make it
possible, together with other modifications, to reduce the size of
the entire PCB.
[0028] The invention will be explained below with reference to
exemplifying embodiments thereof that are illustrated in the
accompanying drawing FIGS. 2A-B, 3-4 and 5A-B. In said drawing
figures are disclosed very schematical embodiments of the inventive
switch configuration. Like the typical prior relay switch type
configuration of FIG. 1, the illustrated embodiments of the
invention are all directed to a switching configuration with a two
mode switch function. It shall be emphasized, though, that the
invention shall not be restricted to such a two mode function.
Instead, the invention may likewise be used for other types of
switching configurations where additional signals are to be
transferred, in turn requiring additional mode functions.
Generally, as will become clear from the following description, the
invention therefore, within practical limits, covers embodiments
for the switching of multiple RF signals in an optional number of
modes, as required for different applications.
[0029] In FIGS. 2A-B is very schematically disclosed a first
exemplary embodiment of an inventive switch configuration that may
be applied for switching high power RF signals in a radio unit DRU.
Generally, this particular embodiment is intended for use with high
power RF signals of approximately 1 W and higher. However, it shall
be emphasized that the invention is not restricted to such a
specification of the high power range. As discussed above, it will
in the illustrated embodiment likewise be used for transferring two
separate RF signals S1 and S2 from respective inputs S1 IN and S2
IN to respective outputs S1 OUT and S2 OUT in one mode; and to
combine the RF signals S1 and S2 and transfer the combined signal
S1+S2 to a common output S1+S2 OUT in a second mode. With specific
reference to FIGS. 2A-B the invention provides a switch
configuration, comprising a signal switch device or module 11. In
sharp contrast to the prior relay type switch configuration, said
switch device 11 consists of an RF matched card holder 12 that is
intended for mounting on and connection to a very generally denoted
PCB of a radio unit (not specifically referenced). The device 11
further includes an RF matched switch card 13 that is adapted to be
received in the card holder 12. The invention is based on the
concept of having a switch card 13 that is provided with different
signal contact layouts on different parts of the card and that is
adapted to be received in alternative positions in the card holder
12. Thereby, the card holder 12 and card 13 combination will
provide the desired two mode functions depending upon the chosen
position of the card 13 in the holder 12.
[0030] In the embodiment of FIGS. 2A-B two RF signal inputs S1 and
S2 are separately connected from the PCB to the card holder 12 that
is also connected to ground G. Signal outputs S1 OUT, S2 OUT are
likewise connected from the card holder 12 to the PCB. Finally, a
combiner 5 on the PCB is connected to the card holder 12.
Specifically, the first switch mode card position I is illustrated
in FIG. 2A. In said first card position I, the signal inputs S1 IN
and S2 IN are separately routed by the switch card 13 to the signal
outputs S1 OUT and S2 OUT on the PCB and no signal is routed
through the combiner 5.
[0031] For the second mode function, the switch card 13 is inserted
into the card holder 12 in the second switch mode card position II
that is illustrated in FIG. 2B. In said second card position II,
signals S1 and S2 are separately routed by the switch card 13 from
the signal inputs S1 IN and S2 IN to separate signal connections
(not specifically denoted) on the combiner 5, from which a combined
signal S1+S2 is connected back to the card 13. This combined signal
S1+S2 is then routed by the card 13 to a combined signal output
S1+S2 OUT on the PCB. For this combined signal output S1+S2 OUT may
be used a separate connection or one of the separate signal output
connections.
[0032] The invention, as described, provides a significant cost
reduction when used in applications where radio signals are to be
coupled in different directions, like in a contact switch. In fact,
the holder and two-mode card combination of the invention may in
DRU applications lower the price with more than 90% compared to the
prior relay type switch configuration. Another essential benefit of
this configuration is that in situations where only two status
modes are present in an application, it is possible to integrate
multiple switch functions in one component providing two basic
modes. Additionally, the proposed switch device using only one
component, namely the two position/two mode switch card, instead of
three or maybe more relays depending upon the application, provides
a considerable material and/or weight reduction. Other benefits of
the inventive switch device are: reduced power consumption, less
quality problems, saving of PCB area, lower component cost, easier
handling in logistics and an unshielded simple design. The robust
and manual handling of the switch function can also improve the
yield of products.
[0033] A practical embodiment of the switch device 11 according to
the invention will now be described with reference to FIGS. 3-4 and
5A-B. In FIG. 3, the card holder 12 is illustrated as surface
mounted to a partially illustrated PCB of a radio unit DRU used for
transmitting and receiving RF signals. The card holder part 12 is
preferably made of suitable high temperature plastic. The epsilon
value (dielectric constant) of the used medium is of importance for
the function, since it affects the RF performance. Multiple signal
coupling contact elements in the form of contact springs 15 are
floatingly supported on structural parts 19 of the card holder 12.
The contact elements 15 are provided for contacting contact pads 18
on the DRU circuit board PCB in use, and for establishing a signal
connection between said PCB contact pads 18 and later described
contact pads 16, 17 of the switch card 13. In the exemplifying
embodiment the card holder 12 has twenty contact springs 15, ten on
each side, to offer the accurate contact force. Said contact
springs 15 are shown as floatingly supported within a card
receiving space or pocket 12A delimited generally by an upper wall
12B and an end wall 12C. Between each signal contact S there is a
ground contact G to achieve the correct signal performance.
[0034] In the practical embodiment of the inventive device or
module 11 that is illustrated in FIGS. 3, 4 and 5A-B, a two sided
switch card 13, having a first side 13A (upper flat side in FIG. 3)
and an opposite second side 13B (lower flat side in FIG. 3), is
used with the card holder 12. In this exemplary embodiment the card
13 has a different contact pattern or layout on each side 13A, 13B,
which set the switch card 13 in different operating modes depending
upon the position of the switch card in the holder 12.
Specifically, two sets of contact pads 16, 17 are provided, with
one set on each of the first and second sides 13A and 13B,
respectively, of the switch card 13. Signal paths SP are extended
between selected contact pads 16, 17 of each set to establish the
two different modes for the switch functions performed by the
device.
[0035] Each side 13A, 13B of the switch card 13 is preferably
provided with means being indicative of the functional position of
the switch card 13 in the card holder 12. The functional position
entered by the card 13 when inserted into the holder 12 is
dependent upon how it is turned, or in other words, which of its
first and second sides 13A and 13B, respectively, that faces
downwardly, contacting the coupling contact elements 15. The
position indicating means may consist of contact pads PI OUT in
each set of contact pads 16 and 17, respectively, on the switch
card 13, for coupling a signal to the printed circuit board PCB of
the DRU confirming that the switch card 13 has been correctly
inserted in the selected position in the card holder 12. Likewise,
each side 13A, 13B of the switch card 13 is preferably provided
with means being indicative of the status of the switch card 13
with regard to its complete insertion into the card holder 12. Said
status indicating means may likewise consist of contact pads SS OUT
in each set of contact pads 16 17, respectively, on the switch card
13 for coupling a signal to the printed circuit board PCB of the
DRU confirming that the switch card 13 has been fully inserted in
the card holder 12.
[0036] It will now be realized that a switch card 13 having two
different layouts on its different first and second sides 13A, 13B,
like in the embodiment of FIGS. 5A-5B, makes it possible to employ
the disclosed holder and card module 11 in configurations for
performing two mode switch functions, as discussed with reference
to FIGS. 2A-B. Accordingly, when the card 13 of FIGS. 5A-B is
introduced into the card receiving space 12A of the holder with its
first side 13A, having the set of contact pads 16 (FIG. 5A), facing
the contact elements 15, this corresponds to the card position I of
FIG. 2A. In particular it will be seen that the signal paths SP of
the layout of said first card side 13A route the signal inputs S1
IN and S2 IN directly to the respective signal outputs S1 OUT and
S2 OUT. Likewise, when the card 13 of FIGS. 5A-B is introduced into
the card receiving space 12A of the holder with its second side
13B, having the set of contact pads 17 (FIG. 5B), facing the
contact elements 15, this corresponds to the card position II of
FIG. 2B. In particular it will be seen that the signal paths SP of
the layout of said second card side 13B route the signal inputs S1
IN and S2 IN to the combiner and then route the combined signal
output S1+S2 from the combiner to the assigned signal output S1+S2
OUT.
[0037] A possible further development of the inventive card 13 is
also indicated in FIGS. 5A-B, according to which the switch card 13
may in itself be made up of or may alternatively include a switch
board 14 in a form of a printed circuit board. Such a card may be
made of standard PCB material but shall be matched for the specific
application wherein it will be used. Using such a PCB type switch
card 13 or switch board 14 it will also be possible to integrate
one or several chip components 20 (see FIG. 5A) on the switch card
13 to assign further functions to the device 11.
[0038] Although the invention has been described and illustrated
with specific reference to practical embodiments thereof as well as
to an exemplary application thereof in a radio unit, the invention
is in no way restricted to such embodiments or to such
applications. The basic principles of the invention may therefore,
in the widest scope of the invention, be applied to any type of
present or future electronic appliance requiring switching of RF
signals.
[0039] In alternative, but not specifically illustrated embodiments
of the invention variations of the switch configuration may be
employed without departing from the scope of the invention. One
example thereof is the theoretically possible variation of having
two different layouts or patterns on one and the same side of the
card, positioned in an area close to the respective short ends of
the card. In other words, to change the position of such a card it
would not be turned upside down but would instead be rotated around
an axis being perpendicular to the upper and lower flat sides
thereof. It would even be possible, in a further variation, to
provide a four mode switching configuration by having two such card
end area layouts on each of the first and second flat sides
thereof.
[0040] The invention likewise covers other configurations including
modified designs of the different illustrated parts of the device,
intended for other applications. Among such modifications that are
covered by the invention are; the shape and number of the holder
contact elements, the actual card holder structure, the size of the
card and card holder, the number of connections etc.
[0041] Although the invention has been described and illustrated
herein in connection with what is presently considered the most
practical and preferred embodiments and applications thereof, it
should be understood that the invention is in no way restricted to
such disclosed embodiments and applications. The invention is
therefore intended to cover various modifications and equivalent
arrangements included within the appended claims.
* * * * *